Is it ensure, insure, or assure?
full of excitement or interest; eager, keen
Old French en gogues 'in mirth'
used with on, upon, for, with, about
"in a state of desire; in a state of imagination; heated with the notion of some enjoyment; longing" [Johnson], c.1400, perhaps from Old French en gogues "in jest, good humor, joyfulness," from gogue "fun," of unknown origin.